Aluminum die-casting machine



Feb. l2, 1952 W. B. BEUSCHER ALUMINUM DIE CASTING MACHINE Filed May. 23, 1949 Patented Feb. 12, 1952 UNITED STATES ATENT OFFICE ALUMINUM DIE-CASTING MACHINE Application May 23, 1949, Serial No. 94,808

4 Claims. (Cl. 2268) This invention relates to analuminum diecasting machine having a shot cylinder assembly.

The principal object of the present invention is Vthe provision of an aluminum diecasting machine having a'fast moving plunger with an extra thrust at the latter portion of the strokes which is accomplished without the use of excessive line pressure or expensive pump equipment.

Another object is to provide means to unload or relieve extra thrust to said plunger before opening the dies of said machine.

A 'further object is to provide means to regulate the thrust, to said plunger to any desired degree.

Other objects are economy of construction, ease andeiciency of operation and adaptability for use with diecasting machines for the casting ,of materials of various compositions.

With these objects in view as well as other objects which will appear in the course of the specification, reference will be had to the drawing wherein the single drawing .is a diagrammatic view of an aluminum diecasting machine, which is better and more completely shown in my copending application, Serial No. 700,413, filed October 1, 1946, now matured into Patent No. 2,492,259, and also in the drawing is a diagrammatic showing of the associated hydraulic equipment embodying the present invention.

In the drawing like reference characters refer to similar parts and the numeral I4 designates a machine base provided adjacent its one end with a .vertically disposed fixed platen I6 to which the stationary part I8 of the die or mold 20 is rigidly attached.

.Adjustably mounted on the other end of base I 4 is an end plate 22. Parallel tie bars 24 tie the fixed. platen vlli and the end `plate 22 together. The movable part 34 of the die or mold is mounted on a movable platen 36 which is slidably mounted on the parallel tie bars 24.

To effect the desired opening and closing of the die members, a reciprocating movement is imparted to the movable platen 36 by a toggle linkage comprising side bars 38, toggle links 40, cross head 42, and a piston rod 44. Toggle links 130 are respectively pivotally connected to side bars 3B by means of pin 39 and to cross head 42 by a pin 4|, and side bars 38 are pivoted to platen 36 by pins 43. A cylinder 46 is provided with means to receive fluid under pressure, which serves to move the piston 41 to drive piston rod 44.

The shot cylinder 50 and the booster cylinder 52 -are important elements which will be further explained in `their operations to deliver molten metal into the die,

Shot cylinder 50 is rigidly Afixed in relation Lto base le, and is provided with a piston 53 to' which a piston rod 54 is mounted for reciprocationjby the action of uid pressure alternately fed-topp-l posite ends of said cylinder. Pistonl rodr54' canried by piston 53 extends through the inner end of cylinder 50. A plunger 58 mounted onth'e end of piston rod 54 operatively ts in bore 60 leading to the mold cavity, and when the piston52 is atits outer end of travel the plunger 58 will ybemoved to uncover metal inlet port'614. `Withthe plunger in this position, molten metal will flow iintobore 60 so that with the next stroke of the piston 53a charge vof metal will be forced into the die-"mold Booster cylinder 52 mounted on cylinder y5|] is provided with a piston 66 ofrelatively small diameter carrying a piston rod 68 which extends into shotcylinder 5E! ahead of piston 53.

At the lower Yleft hand corner of the sheet of drawing is shown an open tank |0, pumps 12 and 'l which are driven by a motor V'16. At the eX- treme right ofthe drawing isanaccumulator 118 to store up a large volume of oil or other vhy draulic fluid which is'purnpedr in through pipe 30 by pump 'l2 to the .bottom of the accumulator against a predetermined volume of vnitrogen or some other inert gas contained .in said accumulator. The pressure inthe accumulator willtrise to the normal delivery pressure of the pump and will have instant delivery to the shot cylinder 550 when the control valve is opened. VPipeillll is provided with a check valve 82 to prevent reverse flow, and with a shut-oir valve 8 4. Throughout the drawing it will be. noted that the operative pressure pipes vare indicated by double lines,v while the control pressure pipes are indicated by single lines.

A pilot valve 86 is connected to pipe 80'byl pipes 8.8 and 90, and an exhaust :line 92 returns from said pilot valve to tank l0. Pipe.94 interconnects valve 66 with shot cylinder 50fahead of ,piston 53 through athrottling valve 96 and spring'lo'aded cheek Valve 98. Pipe |00 connects valve y86 with cylinder 50 behind piston 53. Pilot valve 85 is controlled by a sliding spool |02. It will be noted that when said spool is inits left position as shown in the drawing, fluid .from pressure pipe will pass through pipe 8 8', pilot valve'86, pipe 94, throttling valve 96, and check valve98 to shot cylinder 50, forcing piston 53 to the left. At the same timeyfluid contained in cylinder 50 behind piston 53 will be exhausted throughpipe |00, valve 86, and pipe 92 to tank l0. When spool |02 is moved to the right, iiuidgwill pass through pipe 90, pilot valve' 86 and pipe; |00 "to 3 cylinder 50 behind piston 53, forcing said piston to the right, and fluid ahead of said piston will be exhausted through pipe 94, valve 8G, and pipe 62 to tank 10, check valve 38 being opened to permit reverse flow by means hereinafter described.

The opposite ends of spool |02 of pilot valve 86 are formed to present pistons |04 and |06 respectively, disposed incavities in the valve body and adapted to be acted upon by fluid under pressure to operate the spool. Fluid for this purpose is furnished by control valve |08, which is of the rotary plug type controlled manually by handle |0. When said handle is moved clockwise as shown, fluid under pressure from pump 12 passes through pipes ||2 and ||4, through control valve |08 to pipe I6, and thence to pilot valve 86 to act on piston |04 to move spool |02 to the left. At the same time, fluid exhausted by piston |06 passes through pipes ||8 and |20, control valve |08, pipe |22, and pipe |24 to tank 10. When handle is moved counter-clock- Wise, fluid entering control valve |08 is connected with pipe |20, and thence through pipe ||8 to act on piston |06 to move spool |02 to the right. Fluid exhausted at this time by piston |04 flows through pipe 6, control valve 08, and tank return pipes |22 and |24. Pipe |20 is also connected with spring loaded check valve 98, and is adapted to supply fluid for operating a piston |26 adapted to open said valve.

Pipe 84 leading from pilot valve 86 to shot cylinder 50 is also connected with booster cylinder 62 ahead of piston 66 by means of pipe |28, in which are inserted throttling valve |30, and adjustable pressure regulator valve |32. A cross connecting pipe |34 interconnects pipes 94 and |28, and a valve |36 is inserted in said by-pass pipe. Said valve is of the sliding piston type, and is spring loaded to be held normally closed. Fluid under pressure from pump 12 flows through pipe ||2, push button valve |38, and pipe |40 to relief valve |36, where it acts on piston |42 to open said valve. Valve |38 is spring loaded to normally maintain connection between pipe |40 and tank return line |24. Only when said valve f is depressed manually is pipe |40 connected with pressure line i l2.

Die operating piston 41 is controlled by a pilot valve |44 and a control valve |46 similar to pilot valve 86 and control valve |08 which operate the Y shot and booster pistons. Pipes |48 and |50 interconnect pump 14 with pilot valve |44, and exhaust pipe |52 returns from said valve to tank i10. Pipes |54 and |56 interconnect said pilot valve with cylinder 46 respectively in front of and behind piston 41. Pilot valve |44 is controlled by a sliding spool |58. When said spool is at the right end of its travel as shown in the drawing, fluid under pressure from pump 14 flows through pipe |48, valve |44, and pipe |54 to cylinder 46, forcing piston 41 to the right, and fluid behind said piston is exhausted through pipe |56, valve |44, and pipe |52 to tank 10. When spool |58 is at the left end of its travel, iiuid from pump 14 ows through pipe |50, valve 44, and pipe l|56 to cylinder 46 to force piston 41 to the left, and fluid in front of said piston is exhausted through pipe 54, valve |44, and pipe |52. The opposite ends of spool |58 are formed to present pistons |60 and |62 respectively for moving said spool. Fluid for actuating said pistons is furnished bycontrol valve |46 similar to valve |08 and having va. manual operating handle |64. When saidhandle is moved clockwise as shown in the drawing, fluid from pump 14 flows through pipes |48 and |66 to valve |46, and is connected thereby with pipe |68, which delivers fluid to the left end of pilot valve |44 to actuate piston i60. When handle |64 is moved counter-clockwise, fluid entering valve |46 through pipe |66 is connected with pipe |10, which delivers fluid to the right end of pilot valve |44 to actuate piston |62. Fluid exhausted by pistons |60 and |62 is returned from valve |46 to tank return line |24 by pipe |12.

The operation of the diecasting machine is substantially as follows. With the machine open, with both the die operating piston 41 and shot piston 53 retracted, the operator first moves handle |64 of control valve |46 clockwise, as shown in the drawing. Fluid under pressure then flows from pump 14 through pipes |48 and |06, valve |46, and pipe |68 to pilot valve |44, actuating piston |60 to move valve spool |58 to the right. Fluid then flows through pipe |48, pilot valve |44, and pipe |54 to cylinder 46 ahead of piston 41, forcing said piston to the right to move the movable platen 36 to the right to bring the die members 34 and |8 together. When the die is closed, side bars 38 of the toggle mechanism are pivoted outwardly by toggle links to engage shoes to lock the dies in the closed position. A suitable charge of molten metal is then introduced into bore 60 of ilxed platen I8 ahead of plunger 58 through port 64, by any suitable means not shown. The operator then moves handle ||0 of control valve |08 clockwise, as shown in the drawing, thereby permitting fluid under pressure to ilow from pump 12 through pipes ||2 and ||4, valve |08, pipe ||6 to pilot valve 36, where it actuates piston |04 to move valve spool |02 to the left. Fluid from pump 12 then ows through pipe 80, pipe 88, valve 86, pipe 94, throttling valve 96, and check valve 88 to shot cylinder 50, forcing piston 53 to the left, whereby plunger 58 forces the charge of molten metal into the die cavity. At the same time, fluid pressure passes through pipes |28, throttling valve |30, and regulating valve |32 to booster cylinder 52, advancing booster piston 66. Thus the shot and booster pistons move simultaneously, but throttling valve |30 restricts fluid flow to the booster cylinder so that the shot piston 53 completes its stroke before booster piston 66 completes its stroke.

When the fluid pressure in shot cylinder reaches full pump pressure, uid flow through pipe 94 ceases and check valve 98 closes automatically, and piston 53l stops movement because the mold cavity has become lled with molten metal. However, uid continues to flow through pipe |28, and booster piston 66 continues to move forwardly, whereby piston rod 6.8 displaces fluid in cylinder 50. The pressure in cylinder 50 is thereby increased to a level equal to the pressure introduced into booster cylinder 52 multiplied by the ratio of the areas of piston 06 and piston rod 68. The increased booster pressure in shot cylinder 50 produces additional forward movement of shot piston 53 and plunger 58, and thereby functions to feed additional metal into the die mold, to feed the-shrink of the casting, redue the porosity of the casting, and provide a" smoothersurface on the casting. The speed of" f the stroke of shot piston 53 may be regulated byi throttling valve 96, and throttling valve |30 is adjusted to provide the speed differential in the strokes of pistons 53 and 66 as previously described. The magnitude of the pressure supplied by the booster piston may be controlled by regulating valve. |132, which closes automatically Whenever the filuld .pressure supplied vto cylinder 522reaches a predetermined level.

It willbe'noted'thatthe entire'booster pressure is 'transmitted through plunger 58, the casting, and movable platen'36 to the die-operatingtoggle mechanism. If said toggle mechanism were opened whilethe extreme booster lpressure was being applied, it would be subjected `to violent shocks `which .would shorten the life of themal chine.` Thus, as the first step in opening the machine. thefoperatormanually depresses pushbutton valve |38 to interconnect pump pressure line '1| 2rwith-pipe |40, `whereby fluid is conducted to relief valve |36 to open said? valveby Vi'actuating piston 42. The .opening of.. said'valve Vby-passes fluidk .from shot cylinder 50 to pipe |28, which isfat pumpV pressure. The pressure in 'Cylinder 501s thereby reduced to pu'mp pressure, andthe .dies may be opened under 'this load without damage to the toggle mechanism. While Vholding lvalve |38 depressed, the-operator turns'handle .|64 o'f control valve |46 counter-clockwise, thus admitting Iluid under pressureto pipe |'to actuatepiston |62 to move spool `|58 of pilot valve l|414 tothe left. Fluid under pressure from pump 14 .thereupon ilowsA through pipe 150, pilot .valve |44, and pipe |56 to cylinder 46 behind piston All, forcing said piston to the left to open the die members. As the die members separate, the pressure in shot cylinder 50 drops, check valve 88 opens, and additional uid flows into said cylinder to force piston 53 still farther to the left. Plunger 58 is thereby advanced to eject the residual slug of metal from bore 60. When said slug has been ejected, the operator moves handle ||0 of control valve |08 counterclockwise, thereby supplying fluid under pressure to pipes and H8, whereby check valve 98 is opened and spool |02 of pilot valve 86 is moved to the right. Fluid under pressure from pipe 80 then flows through pipe 90, pilot valve 86, and pipe |00 to cylinder 50 behind piston 53, forcing said pistonv to the right. Piston 458 strikes the inner end of piston rod 68 and forces piston 66 to its retracted position. Fluid ahead of piston 53 is exhausted through pipe 94, open check valve 98, valve 96, pilot valve 86, and pipe 92 to tank 10, Fluid ahead of booster piston 66 is exhausted through pipe |28, regulating valve |32, and valve |30 to pipe 94, The machine is then ready for repetitions of the cycle as desired.

Thus it is apparent that a die-casting machine having several advantages has been produced. The injection pressure builds up smoothly and without steps from zero to many times pump pressure.

The magnitude and speed of thrust are readily adjustable Expensive pumping equipment and excessive line pressures are not necessary to produce to booster pressure. Check valve 98 and relief valve |36 are the only valves subjected to the multiplied pressure and it is contemplated that these valves be built directly into the thickened walls of shot cylinder 50. The die-operating toggle mechanism is protected from damage by excessive pressure. It is obvious that control valve |46 and push-button valve |38 could be so related, either mechanically or hydraulically, that the dies could not be opened so long as full booster pressure is being applied to the shot piston.

While I have shown a specific embodiment of my invention, it 1s apparent that many minor variations-fcould'be made without departing' from the spirit-of the'invention. f

WhatIclaim is:

l. In a die-casting machine o'f the class denl scribed having a die mold, a plunger adapted `to inject a chargelof molten metal into said mold, a vhydraulicallyoperated shot piston adapted to actuate'said plunger, a hydraulic cylinderrigidly associated with said mold and in which said shot piston operates'a booster-piston, -ahydraulic cylinder rigidly'connected to said shot cylinder and in which ysaid booster piston operates, a rodxed to said booster piston and extending into said shot'cylinder, apair lof lconduits interconnected respectively Withfsaid shot'and booster cylinders, a hydraulic pump interconnected with said Aconduits and operableto deliver nuidunder pressure simultaneously to said cylinders throughI said conduits, whereby said shot piston is advanced to cause saidvplunger to inject molten vmetal into said mold and whereby said booster pistonfis advanced to move saidrod into said shot cylinder todisplace uid therein, a check valve disposed into the conduit leading to said shot cylinder and ,adapted .to prevent reverse flow therein, and a owrestriction disposed in the conduit loading to said booster cylinder, whereby said booster piston is caused to advance more slowly than said shot piston.

2. In a die-casting machine of the class described having a die mold, a plunger adapted to inject a charge of molten metal into said mold, a hydraulically operated shot piston adapted to actuate said plunger, a hydraulic cylinder rigidly associated with said mold and in which said shot piston operates, a booster piston, a hydraulic cylinder rigidly connected to said shot cylinder and in which said booster piston operates, a rod xed to said booster piston and extending into said shot cylinder, a pair of conduits interconnected respectively with said shot and booster cylinders, a hydraulic pump interconnected with said conduits and operable to deliver fluid under pressure simultaneously to said cylinders through said conduits, whereby said shot piston is advanced to cause said plunger to inject molten metal into said mold and whereby said booster piston is advanced to move said rod into said shot cylinder to displace iluid therein, a check valve disposed into the conduit leading to said shot cylinder and adapted to prevent reverse flow therein, and an adjustable throttling valve in each of said conduits whereby the relative rate of movement of said pistons may be adjusted.

3. In a die-casting machine of the class described having a die mold, a plunger adapted to inject a charge of molten metal into said mold, a hydraulically operated shot piston adapted to actuate said plunger, a hydraulic cylinder rigidly associated with said mold and in which said shot piston operates, a booster piston, a hydraulic cylinder rigidly connected to said shot cylinder and in which said booster piston operates, a rod xed to said booster piston and extending into said shot cylinder, a pair of conduits interconnected respectively with said shot and booster cylinders, a hydraulic pump interconnected with said conduits and opera-ble to deliver iluid under pressure simultaneously to said cylinders through said conduits, whereby said shot piston is advanced to cause said plunger to inject molten metal into said mold and whereby said booster piston is advanced to move said rod into said shot cylinder to displace fluid therein, acheck valve disposed into the conduit leading to said shot cylinder and adapted to prevent reverse flow therein, a ow restriction in the conduit leading to said booster cylinder, whereby said booster piston is caused to advance more slowly than said shot piston, and a pressure regulating valve disposed in said last named conduit intermediate said iiow restriction and said booster cylinder.

, 4. In a die-casting machine of the class described having a die mold, a plunger adapted to inject a charge of molten metal into said mold, a hydraulically operated shot piston adapted to actuate said plunger, a hydraulic cylinder rigidly associated with said mold and in which said shot piston operates, a. booster piston, a hydraulic cylinder rigidly connected to said shot cylinder and in which said booster piston operates, a rod fixed to said booster piston andl extending `to said shot cylinder, a pair of conduits interconnected respectively with said shot and booster cylinders, a hydraulic pump interconnected with said conduits and operable to deliver iiuid under pressure simultaneously to said cylinders through said conduits, whereby said shot piston 'is advanced i,

to cause said plunger to inject molten metal into said mold and whereby said Ibooster piston is advanced to move said rod into said shot cylinder valve.. l WILLIAM B. BEUSCHER.

REFERENCES CITED The following references are of record in the le of this patent:

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